A war weary Korean girl carries her brother on her back, with a stalled M-26 tank in the background, in Haengju, Korea, June 1951. (National Archives and Records Administration; U.S. Department of Defense)

At the conclusion of World War II, the Japanese
army, which had occupied Korea for 35 years, finally surrendered.
This surrender marked the end of a brutal regime in which Koreans
had been relegated to second-class citizens in their own country.

Under Japanese rule, the Korean language was taboo. Japanese
was enforced as the official language. Koreans were even forced
to abandon their names and assume new ones provided by their
colonizers. When Russian and American troops helped liberate
the country at the close of the war, Koreans embraced the soldiers.

But as new occupying forces divided the country in half, Koreans
found themselves torn between two blossoming superpowers with
divergent ideologies. In the South, U.S. generals installed
a hard-line anticommunist, Syngman Rhee, as South Korea's first
president. (Syngman Rhee had spent decades in exile in the United
States.) In the North, where Russians were in control, Kim Il-sung,
who had lived in the Soviet Union during the war, was installed
in power.

As Soviet troops gradually withdrew from the North in the
years that followed, Kim dreamed of uniting Korea under communism.
Kim sought approval from Soviet dictator Joseph Stalin to invade
the South. But Stalin was preoccupied with a crisis in Berlin
(where Soviets also faced off against the United States), and
he didn't support Kim's planned invasion.

A U.S. soldier serving in the Korean War receives a fond farewell from his family, November 1950. More than one and a half million U.S. soldiers served in the three-year conflict. (National Archives and Records Administration; U.S. Department of Defense)

By the end of the decade, the international situation had shifted.
The Soviets had detonated their first atom bomb. China was offering
a new model for communist revolution. A treaty between Chinese
leader Mao Tse-tung and Stalin created a global communist alliance.
And Kim finally got the green light for his reunification plan.

On June 25, 1950, in a surprise attack, North Korean soldiers,
who were directed by Soviet advisors and equipped with Russian
tanks and artillery, flooded into the South. The invaders took
Seoul in three days.

Ten days later, the first U.S. soldiers arrived on the peninsula.

At the time, a "Red scare" led by Senator Joseph McCarthy
was under way in the United States. When President Harry Truman
addressed the nation on July 19, 1950, he warned Americans of
the spread of communism. "Korea is a small country, thousands
of miles away, but what is happening there is important to every
American," he said. "The fact that communist forces have invaded
Korea is a warning that there may be similar acts of aggression
in other parts of the world."

Within just months of Truman's address, hundreds of thousands
of U.S. soldiers, as well as troops from more than a dozen other
nations, were serving under the United Nations flag to protect
South Korea.

The lead bomber of the Far East Air Forces 19th Bomber Group on its 150th combat mission in the Korean War. (National Archives and Records Administration; U.S. Department of Defense)

Then on September 15, 1950, United Nations American commander
General Douglas MacArthur led a daring, amphibious counter-invasion
near Seoul. Hundreds of warships carrying nearly 70,000 men
landed at the port of Inchon despite dangerous tides. Their
landing quickly cut off North Korean supply lines and forced
the army to flee north.

After United Nations troops took back Seoul, a few units pressed
as far north as North Korea's border with communist China. Their
advance triggered a counter-attack by the Chinese, who had warned
they would not accept a U.N. takeover of North Korea. More than
300,000 Chinese soldiers massed, forcing the United Nations
forces to evacuate and abandon their vehicles and equipment.

China continued to send in waves of soldiers to fight for
North Korea. In response, General MacArthur advocated attacking
bases inside China. But President Truman feared that such an
attack could plunge the entire world into World War III. (Truman
eventually stripped MacArthur of his command.)

The Korean War raged for three more years. When a truce was
reached in July 1953, more than 3 million Koreans had been killed,
wounded or were missing. In addition, 900,000 Chinese had been
killed or wounded. More than 54,000 American soldiers, 1,000
British soldiers and 4,000 soldiers from other countries also
died on Korean battlefields.

Yet after all the killing, the border between the two Koreas
at the 38th parallel had hardly changed.